Canary Deployment - Canlıya Geçirme - Yükün Belli Bir Yüzdesi Yeni Sisteme Verilir

Giriş

Açıklaması şöyle.  İki farklı deployment yan yana çalışır. Yükün belli bir yüzdesi yeni sisteme verilir

Canary deployment strategy is used to carry out A/B testing and dark launches. It is similar to the blue-green approach but more controlled. We will see slow-moving traffic from version A to version B in this strategy. Think: canary in the coal mine!

Yüzde ile ilgili açıklam şöyle. 

Finally, in a Canary deployment, a new application replica is added to the load balancer, and the load balancer is configured to pass only a specific percentage of the application traffic to the new replica. Once configured, a full analysis of the traffic volume, response times, or activity on the replica is performed. If the analysis is successful, this deployment generally continues as a Rolling deployment.

Örnek

Şöyle yaparız. Tek path var. 

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: sample-api-ing
  namespace: default
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$1 
spec:
  rules:
    - host: sample-api.com
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: sample-api-svc
                port:
                  number: 8080

Service şöyledir. Bu service Ingress tarafından kullanıldığı için type ClusterIP

apiVersion: v1
kind: Service
metadata:
  name: sample-api-svc
  namespace: default
  labels:
    app: sample-api
spec:
  type: ClusterIP         <----
  selector:
    app: sample-api
  ports:
  - port: 8080
    name: "http"
    protocol: TCP

Birinci deployment şöyle. Bu deployment .net ile gerçekleştiriliyor.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: sample-api-app              <----
  namespace: default
spec:
  replicas: 4                       <----
  selector:
    matchLabels:
      app: sample-api
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 20%
  template:
    metadata:
      labels:
        version: "netcore6"         <----
        app: sample-api
    spec:
      containers:
      - name:  sample-api
        image: localhost:5000/sample-api-netcore
        imagePullPolicy: Always
        ports:
        - containerPort: 8080
        env:
        - name: ASPNETCORE_URLS 
          value: http://*:8080

İkinci deployment şöyle. Bu deployment GoLang ile gerçekleştiriliyor.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: sample-api-canary-app         <----
  namespace: default
spec:
  replicas: 1                         <----
  selector:
    matchLabels:
      app: sample-api
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 20%
  template:
    metadata:
      labels:
        version: "golang"             <----
        app: sample-api
    spec:
      containers:
      - name:  sample-api
        image: localhost:5000/sample-api-golang
        imagePullPolicy: Always
        ports:
        - containerPort: 8080

Böylece iki farklı deployment yan yana çalışıyor.